This document describes differences between the 5.12.1 release and the 5.12.2 release.

If you are upgrading from an earlier major version,
such as 5.10.1,
first read perl5120delta,
which describes differences between 5.10.1 and 5.12.0,
as well as perl5121delta,
which describes earlier changes in the 5.12 stable release series.

Carp now detects incomplete caller() overrides and avoids using bogus @DB::args.
To provide backtraces,
Carp relies on particular behaviour of the caller built-in.
Carp now detects if other code has overridden this with an incomplete implementation,
and modifies its backtrace accordingly.
Previously incomplete overrides would cause incorrect values in backtraces (best case),
or obscure fatal errors (worst case)

Several portability fixes were made in File::Spec::VMS: a colon is now recognized as a delimiter in native filespecs; caret-escaped delimiters are recognized for better handling of extended filespecs; catpath() returns an empty directory rather than the current directory if the input directory name is empty; abs2rel() properly handles Unix-style input.

alarm()'s inability to interrupt blocking IO on Windows has been documented.

Math::TrulyRandom hasn't been updated since 1996 and has been removed as a recommended solution for random number generation.

perlrun has been updated to clarify the behaviour of octal flags to perl.

To ease user confusion,
$# and $*,
two special variables that were removed in earlier versions of Perl have been documented.

The version of perlfaq shipped with the Perl core has been updated from the official FAQ version,
which is now maintained in the briandfoy/perlfaq branch of the Perl repository at git://perl5.git.perl.org/perl.git.

A possible memory leak when using caller() to set @DB::args has been fixed.

Several memory leaks when loading XS modules were fixed.

unpack() now handles scalar context correctly for %32H and %32u,
fixing a potential crash.
split() would crash because the third item on the stack wasn't the regular expression it expected.
unpack("%2H",
...) would return both the unpacked result and the checksum on the stack,
as would unpack("%2u",
...).
[perl #73814]

Perl now avoids using memory after calling free() in pp_require when there are CODEREFs in @INC.

A bug that could cause "Unknown error" messages when "call_sv(code,
G_EVAL)" is called from an XS destructor has been fixed.

The implementation of the open $fh,
'>' \$buffer feature now supports get/set magic and thus tied buffers correctly.

The pp_getc,
pp_tell,
and pp_eof opcodes now make room on the stack for their return values in cases where no argument was passed in.

When matching unicode strings under some conditions inappropriate backtracking would result in a Malformed UTF-8 character (fatal) error.
This should no longer occur.
See [perl #75680]

When building Perl with the mingw64 x64 cross-compiler incpath,
libpth,
ldflags,
lddlflags and ldflags_nolargefiles values in Config.pm and Config_heavy.pl were not previously being set correctly because,
with that compiler,
the include and lib directories are not immediately below $(CCHOME).

If you find what you think is a bug,
you might check the articles recently posted to the comp.lang.perl.misc newsgroup and the perl bug database at http://rt.perl.org/perlbug/ .
There may also be information at http://www.perl.org/ ,
the Perl Home Page.

If you believe you have an unreported bug,
please run the perlbug program included with your release.
Be sure to trim your bug down to a tiny but sufficient test case.
Your bug report,
along with the output of perl -V,
will be sent off to perlbug@perl.org to be analysed by the Perl porting team.

If the bug you are reporting has security implications,
which make it inappropriate to send to a publicly archived mailing list,
then please send it to perl5-security-report@perl.org.
This points to a closed subscription unarchived mailing list,
which includes all the core committers,
who will be able to help assess the impact of issues,
figure out a resolution,
and help co-ordinate the release of patches to mitigate or fix the problem across all platforms on which Perl is supported.
Please only use this address for security issues in the Perl core,
not for modules independently distributed on CPAN.